118 research outputs found
Organizational culture and climate as moderators of enhanced outreach for persons with serious mental illness: results from a cluster-randomized trial of adaptive implementation strategies
Abstract
Background
Organizational culture and climate are considered key factors in implementation efforts but have not been examined as moderators of implementation strategy comparative effectiveness. We investigated organizational culture and climate as moderators of comparative effectiveness of two sequences of implementation strategies (Immediate vs. Delayed Enhanced Replicating Effective Programs [REP]) combining Standard REP and REP enhanced with facilitation on implementation of an outreach program for Veterans with serious mental illness lost to care at Veterans Health Administration (VA) facilities nationwide.
Methods
This study is a secondary analysis of the cluster-randomized Re-Engage implementation trial that assigned 3075 patients at 89 VA facilities to either the Immediate or Delayed Enhanced REP sequences. We hypothesized that sites with stronger entrepreneurial culture, task, or relational climate would benefit more from Enhanced REP than Standard REP. Veteran- and site-level data from the Re-Engage trial were combined with site-aggregated measures of entrepreneurial culture and task and relational climate from the 2012 VA All Employee Survey. Longitudinal mixed-effects logistic models examined whether the comparative effectiveness of the Immediate vs. Delayed Enhanced REP sequences were moderated by culture or climate measures at 6 and 12 months post-randomization. Three Veteran-level outcomes related to the engagement with the VA system were assessed: updated documentation, attempted contact by coordinator, and completed contact.
Results
For updated documentation and attempted contact, Veterans at sites with higher entrepreneurial culture and task climate scores benefitted more from Enhanced REP compared to Standard REP than Veterans at sites with lower scores. Few culture or climate moderation effects were detected for the comparative effectiveness of the full sequences of implementation strategies.
Conclusions
Implementation strategy effectiveness is highly intertwined with contextual factors, and implementation practitioners may use knowledge of contextual moderation to tailor strategy deployment. We found that facilitation strategies provided with Enhanced REP were more effective at improving uptake of a mental health outreach program at sites with stronger entrepreneurial culture and task climate; Veterans at sites with lower levels of these measures saw more similar improvement under Standard and Enhanced REP. Within resource-constrained systems, practitioners may choose to target more intensive implementation strategies to sites that will most benefit from them.
Trial registration
ISRCTN:
ISRCTN21059161
. Date registered: April 11, 2013.https://deepblue.lib.umich.edu/bitstream/2027.42/144775/1/13012_2018_Article_787.pd
Multi-point Assessment of the Kinematics of Shocks (MAKOS): A Heliophysics Mission Concept Study
Collisionless shocks are fundamental processes that are ubiquitous in space
plasma physics throughout the Heliosphere and most astrophysical environments.
Earth's bow shock and interplanetary shocks at 1 AU offer the most readily
accessible opportunities to advance our understanding of the nature of
collisionless shocks via fully-instrumented, in situ observations. One major
outstanding question pertains to the energy budget of collisionless shocks,
particularly how exactly collisionless shocks convert incident kinetic bulk
flow energy into thermalization (heating), suprathermal particle acceleration,
and a variety of plasma waves, including nonlinear structures. Furthermore, it
remains unknown how those energy conversion processes change for different
shock orientations (e.g., quasi-parallel vs. quasi-perpendicular) and driving
conditions (upstream Alfv\'enic and fast Mach numbers, plasma beta, etc.).
Required to address these questions are multipoint observations enabling direct
measurement of the necessary plasmas, energetic particles, and electric and
magnetic fields and waves, all simultaneously from upstream, downstream, and at
the shock transition layer with observatory separations at ion to
magnetohydrodynamic (MHD) scales. Such a configuration of spacecraft with
specifically-designed instruments has never been available, and this white
paper describes a conceptual mission design -- MAKOS -- to address these
outstanding questions and advance our knowledge of the nature of collisionless
shocks.Comment: White paper submitted to the Decadal Survey for Solar and Space
Physics (Heliophysics) 2024-2033; 9 pages, 3 figures, 5 table
The quasar fraction in low-frequency selected complete samples and implications for unified schemes
Low-frequency radio surveys are ideal for selecting orientation-independent
samples of extragalactic sources because the sample members are selected by
virtue of their isotropic steep-spectrum extended emission. We use the new 7C
Redshift Survey along with the brighter 3CRR and 6C samples to investigate the
fraction of objects with observed broad emission lines - the `quasar fraction'
- as a function of redshift and of radio and narrow emission line luminosity.
We find that the quasar fraction is more strongly dependent upon luminosity
(both narrow line and radio) than it is on redshift. Above a narrow [OII]
emission line luminosity of log L_[OII] > 35 W (or radio luminosity log L_151 >
26.5 W/Hz/sr), the quasar fraction is virtually independent of redshift and
luminosity; this is consistent with a simple unified scheme with an obscuring
torus with a half-opening angle theta_trans approx 53 degrees. For objects with
less luminous narrow lines, the quasar fraction is lower. We show that this is
not due to the difficulty of detecting lower-luminosity broad emission lines in
a less luminous, but otherwise similar, quasar population. We discuss evidence
which supports at least two probable physical causes for the drop in quasar
fraction at low luminosity: (i) a gradual decrease in theta_trans and/or a
gradual increase in the fraction of lightly-reddened (0 < A(V) < 5)
lines-of-sight with decreasing quasar luminosity; and (ii) the emergence of a
distinct second population of low luminosity radio sources which, like M87,
lack a well-fed quasar nucleus and may well lack a thick obscuring torus.Comment: 10 pages, 4 figures, accepted for publication in MNRA
The Persistent Mystery of Collisionless Shocks
Collisionless shock waves are one of the main forms of energy conversion in
space plasmas. They can directly or indirectly drive other universal plasma
processes such as magnetic reconnection, turbulence, particle acceleration and
wave phenomena. Collisionless shocks employ a myriad of kinetic plasma
mechanisms to convert the kinetic energy of supersonic flows in space to other
forms of energy (e.g., thermal plasma, energetic particles, or Poynting flux)
in order for the flow to pass an immovable obstacle. The partitioning of energy
downstream of collisionless shocks is not well understood, nor are the
processes which perform energy conversion. While we, as the heliophysics
community, have collected an abundance of observations of the terrestrial bow
shock, instrument and mission-level limitations have made it impossible to
quantify this partition, to establish the physics within the shock layer
responsible for it, and to understand its dependence on upstream conditions.
This paper stresses the need for the first ever spacecraft mission specifically
designed and dedicated to the observation of both the terrestrial bow shock as
well as Interplanetary shocks in the solar wind.Comment: White paper submitted to the Decadal Survey for Solar and Space
Physics (Heliophysics) 2024-2033; 9 pages, 4 figure
Electron Energy Partition across Interplanetary Shocks. III. Analysis
An analysis of model fit results of 15,210 electron velocity distribution functions (VDFs), observed within 2 hr of 52 interplanetary (IP) shocks by the Wind spacecraft near 1 au, is presented as the third and final part on electron VDFs near IP shocks. The core electrons and protons dominate in the magnitude and change in the partial-to-total thermal pressure ratio, with the core electrons often gaining as much or more than the protons. Only a moderate positive correlation is observed between the electron temperature and the kinetic energy change across the shock, while weaker, if any, correlations were found with any other macroscopic shock parameter. No VDF parameter correlated with the shock normal angle. The electron VDF evolves from a narrowly peaked core with flaring suprathermal tails in the upstream to either a slightly hotter core with steeper tails or much hotter flattop core with even steeper tails downstream of the weaker and strongest shocks, respectively. Both quasi-static and fluctuating fields are examined as possible mechanisms modifying the VDF, but neither is sufficient alone. For instance, flattop VDFs can be generated by nonlinear ion acoustic wave stochastic acceleration (i.e., inelastic collisions), while other work suggested they result from the combination of quasi-static and fluctuating fields. This three-part study shows that not only are these systems not thermodynamic in nature; even kinetic models may require modification to include things like inelastic collision operators to properly model electron VDF evolution across shocks or in the solar wind.Peer reviewe
Electron Energy Partition across Interplanetary Shocks. II. Statistics
A statistical analysis of 15,210 electron velocity distribution function (VDF) fits, observed within +/- 2 hr of 52 interplanetary (IP) shocks by the Wind spacecraft near 1 au, is presented. This is the second in a three-part series on electron VDFs near IP shocks. The electron velocity moment statistics for the dense, low-energy core, tenuous, hot halo, and field-aligned beam/strahl are a statistically significant list of values illustrated with both histograms and tabular lists for reference and baselines in future work. Given the large statistics in this investigation, the beam/strahl fit results in the upstream are now the most comprehensive attempt to parameterize the beam/strahl electron velocity moments in the ambient solar wind. The median density, temperature, beta, and temperature anisotropy values for the core(halo)[beam/strahl] components, with subscripts ec(eh)[eb], of all fit results, respectively, are n(ec(h)[b]) similar to 11.3(0.36)[0.17] cm(-3), T-ec(h)[b],T-tot similar to 14.6(48.4)[40.2] eV, beta(ec(h)[b],tot) similar to 0.93(0.11)[0.05], and Alpha(ec(h)[b]) similar to 0.98(1.03)[0.93]. This work will also serve as a 1 au baseline and reference for missions like Parker Solar Probe and Solar Orbiter.Peer reviewe
Deformation of Crystals: Connections with Statistical Physics
We give a bird's-eye view of the plastic deformation of crystals aimed at the statistical physics community, as well as a broad introduction to the statistical theories of forced rigid systems aimed at the plasticity community. Memory effects in magnets, spin glasses, charge density waves, and dilute colloidal suspensions are discussed in relation to the onset of plastic yielding in crystals. Dislocation avalanches and complex dislocation tangles are discussed via a brief introduction to the renormalization group and scaling. Analogies to emergent scale invariance in fracture, jamming, coarsening, and a variety of depinning transitions are explored. Dislocation dynamics in crystals challenge nonequilibrium statistical physics. Statistical physics provides both cautionary tales of subtle memory effects in nonequilibrium systems and systematic tools designed to address complex scale-invariant behavior on multiple length scales and timescales
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